Valve for steam-engines



(Nomea-l.) l J. S. MARSHALL.,

VALVE FORSTEAM ENGINES.

No. 381,152. Patented Apr. 17, r188.8.l

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s JOHN s. MARSHALL, or IMLAY CITY,immensen.,y

vALVEpVFoR STEAM,-ENeiNtze.Y

SPECIE-marron forming pari: gf Leners PatentfNo. 381,152. dated Aprn 17,1888. Y f f Application filed October 26, 1887. Serial No. 253,46d. (N o model.) v

To all whom t may concern: e y s y Be itvknown that l, JOHN S. MARSHALL, a citizen, of the United States, residing at Imlay City, in the county of Lapeer and State of Michigan, have. invented a new and useful Improvement in Valves for Steam-Engines, of which the following-is a specification.

Y My inventiongrelatesto an improvement in valves vfor steam-engines; and it consists in the peculiar` construction and combination of devices that will be more fully set forth hereinafter, and particularly pointed out in the claims. 1

In the accompanying drawings, Figure 1 is a vertical 'longitudinal sectional view of the operating parts of a steam-engine embodying my improvements; Fig.,2 is a vertical secrcylinder C are cast integrally and are formed of the same piece of metal.

The ends of the steam-chest B project some- A what beyond the ends of the steam-cylinder A,

and the valve-cylinder C is arranged in the side of the chest B, adjacent to the steam-cylinder A. The said valve-cylinder C is of less diameter than the cylindrical chest B, and is also somewhat shorter than the latter, so that a space is formed between the sides and ends of the cylinders-B G. On the ends of thecylindrical steam-chest B are fitted heads D by means of ground joints, and on the ends ofthe steam-cylinder A are fitted heads E by means of ground joints. v

In the center of the valve-cylinder C and extending longitudinally through the same` is al cylindrical bore, F. In opposite ends of the valvecylinder Care formed steam-ports G H, each of iwhich comprises a series of four spiA rally-arranged openings, I, which openings eX- tend entirely around the circumference ofthe bore and communicate with each otherA and with recesses K, that are made in the under side of the valvecylinder and communicate with the ends of the'ste'am-'cylinden arranging the spiral `openings I bridgefpieces L are formed between thesame, which bridgepieces are integral with the cylinder C. Thek centralportionof thebore F intermediate the steam-ports is'enlarged to form an exhaust-V chamber, M, and an opening, N, is made through the sides' of the cylindrical steamthe exhaust-steam passes.

O represents the piston, whichis ofthe usual l and through a packing box formed on the said head. a

By thus chest and valve-cylinder kC, through which R represents a val verod that extends th rough j one of the heads D of the cylindrical steamare cylindrical in shape, are fitted snugly in thel fbore F by means of expansion packinga chestand enters the valve-cylinder C, asshown.`

Secured to the saidk rod are valves S T, which l of the spirally-arran gedfopenin gs Iand bridgepiecesL between the said openings the inner I 1 surface, of the cy'lindricalboreF is preserved unbroken, so that compression is at al1 times maintained on the packing-rings U WhileJthe and the said packing-rings are prevented from expanding and catchingv in' the ports4 as ther 'valves are in position in the valve-cylinder,

understood. Furthermore, the recesses K, which communicate with the openings I and with .ends of the steam-cylinder A, are veryA short, vthe ports being arranged directly over- Vthe endsof the cylinder, and thereby the area of the said recesses K is reduced to a minimum, -and consequently only a' very 'small l quantity of steam remains dead inA the said re-- cesses at each stroke of the piston. Inasmuch as the said recessesK are arranged-directly atw the ends of thefsteam-cylinder only la' yverysk slight space is left between the cylinderheads and the piston at the endsof the strokes of the? .ICCA

latter for dead steam.

.e The operationof my invention is as follows: Live steam is admitted to the cylindrical steam-` chest through a central opening, V, therein j v and is caused to bear against the outerendsof'V the valves S T with equal pressure, thereby balancing the said valves and enabling the .same to be moved lengthwise in 'the valve- -therefore passes through the port G into the rear end of the cylinder A and forces the piston forward, and the dead steam in the said cylinder in front of the piston passes through the port H into the exhaust-chamber M and through the opening N. When the piston reaches the forward limit of its stroke, the valves are moved rearward by suitable gearing or mechanism, which is not here shown, as it forms no part of my present improvement, (and may be of the form ordinarily employed in steam-engines lfor this purpose,) thereby causing the positions of the valves S and T to be the reverse of that shown in Fig. 1', so that the valve S will be on the outer side of the port G and the valve T will be on the inner side of the port H. When thus arranged, steam will be admitted through the port H into the frontend of thesteamcylinder to force the piston rearward therein, and the steam in the rear end of the said cylinder escapes upward through the port G into the exhaust-` chamber M and out through the opening N.

A steam-engine thus constructed will be extremely cheap and simple. It is very readily made and is easily put in running order. By

casting the cylinder A, the cylindrical steamchest B, and the valve-cylinder C in one integral piece, as before described, no packing is required between the steam-c linde? and the 1. In a steam-engine, the combination ofl the steam-cylinder A, having the vertical recesses K Vadjoining its heads and extending transversely from wall to wall, the steam-chest extending fat each end beyond said cylinder and taking steam centrally on top at V, the valve-cylinder provided with the inclined spiral ports -G H, opening directly into the recesses K, and all in the same vertical plane open at its ends to take steam from the steamchest, and having the exhaust-opening at its central port, and the valves S T provided with expansion packing-rings of ordinary construction, substantially as specified.

2. In a steam engine, in combination with the steam-cylinder, the steam-chest extending at each end beyond the said cylinder, and the valve-cylinder within the steam-chest adjoining the steam-cylinder and having ports opening directly thereinto, the said steam-cylinder, steam-chest, and valve-cylinder being cast integral with each other, and the cylinder-heads and steam-chest heads fitted to their seats by ground-joints, substantially as specified.

In testimony that I claim the foregoing as my own I have hereto affixed my signaturein presence of two witnesses.

JOHN S. MARSHALL.

Witnesses:

J oHN H. SIGGERs, E. G. SIGGERs. 

